title: Development of factors to convert frequency to rate for beta-cell replication and apoptosis quantified by time-lapse video microscopy and immunohistochemistry.
abstract: An obstacle to development of methods to quantify beta-cell turnover from pancreas tissue is the lack of conversion factors for the frequency of beta-cell replication or apoptosis detected by immunohistochemistry to rates of replication or apoptosis. We addressed this obstacle in islets from 1-mo-old rats by quantifying the relationship between the rate of beta-cell replication observed directly by time-lapse video microscopy (TLVM) and the frequency of beta-cell replication in the same islets detected by immunohistochemistry using antibodies against Ki67 and insulin in the same islets fixed immediately after TLVM. Similarly, we quantified the rate of beta-cell apoptosis by TLVM and then the frequency of apoptosis in the same islets using TdT-mediated dUTP nick-end labeling and insulin. Conversion factors were developed by regression analysis. The conversion factor from Ki67 labeling frequency (%) to actual replication rate (%events/h) is 0.025 +/- 0.003 h(-1). The conversion factor from TdT-mediated dUTP nick-end labeling frequency (%) to actual apoptosis rate (%events/h) is 0.41 +/- 0.05 h(-1). These conversion factors will permit development of models to evaluate beta-cell turnover in fixed pancreas tissue.
authors.affiliation: Larry Hillblom Islet Research Center, UCLA David Geffen School of Medicine, 900 Weyburn Place #A, Los Angeles, CA 90024-2852, USA.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Saisho
authors.forename: Erica
authors.initials: E
authors.lastname: Manesso
authors.forename: Tatyana
authors.initials: T
authors.lastname: Gurlo
authors.forename: Chang-Jiang
authors.initials: CJ
authors.lastname: Huang
authors.forename: Gianna M
authors.initials: GM
authors.lastname: Toffolo
authors.forename: Claudio
authors.initials: C
authors.lastname: Cobelli
authors.forename: Peter C
authors.initials: PC
authors.lastname: Butler
mesh_terms: D000465:Algorithms; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007328:Insulin / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D007700:Kinetics; D008297:Male; D018715:Microscopy, Video / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007328:Insulin; D019394:Ki-67 Antigen